An Investigation On Composition Of Phenolic Substances, Fatty Acids And Proteins In Seeds Of Transgenic Soybean

The safety of genetically modified soybean (mainly Roundup Ready soybean) aroused worldwide concern and much work on its safety evaluation was carried out in recent years. Glyphosate-tolerant soybean (RR soybean) is a soybean variety introduced an exogenous gene which controls expression of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). EPSPS is a key enzyme in secondary metabolism that would affect phenolic substances metabolism, suggesting that changes in metabolism of phenolic substances would occur comparing with its parent. In this research, phenolic substances were investigated in different fractions of soybean seed from transgenic soybean and its parent, and two conventional varieties. Furthermore, the content and composition of seed fatty acids and protein were also comparatively studied by GC and SDS-polyacrylamide gel electrophoresis respectively. The main results were as follows.1. The phenolic substances were extracted and purified from soybean seeds with an AB-8 macroporous resin column, and phenolic acids were extracted and purified from defatted soybean powder with anion- exchange resin column, which were all tested by HPLC. The results showed that there were significant differences in composition and content of phenolic substances between the tested materials, including RR soybean and its parent. The differences could be found in different fractions of seeds, including oil, protein and pulp.2. There were significant differences in content of fatty acids between the tested materials, but no difference was observed for the composition of fatty acids, indicating that genetically-modification in soybean would quantitatively but not qualitatively affect metabolism of fatty acids.3. Protein composition of soybean seed protein changed after genetically-modification, the RR soybean had a special protein band with molecular weight of 40KD.